gas smell coming from the AC/Heater vent

[n2knee]

This is my post from another forum.


I recently purchased a second car. It is a 1991 Nissan Stanza. When the engine is on there is gas smell coming from the ac/heater vent. It gets worse when I turn the heater or ac on. What could be causing this problem and how to fix it? Your help is greatly appreciated!

 

[TPLYNCH]

Do you smell it if you open the hood while it's running. My guess would be leak in your fuel line.

 

[n2knee]

I can smell it when I'm in the car. The smell is worse when the car is parked and I'm near the hood. I'm going to get the fuel lines inspected. How much do you think it may cost me?

 

[Robb]

Do you smell it when it is in max a/c (recycle)?

 

[n2knee]

Originally posted by morrisey0
Do you smell it when it is in max a/c (recycle)?

anytime I turn the ac/heater on. there are also instances where I just put the car at idle and the smell just overwhelms the interior of the car.

 

[Robb]

About the max a/c comment? Anytime your blower is on other than max a/c, it is pulling "fresh" air, probably from the cowling area between your windshield and engine compartment. If the gasket between the cowling and engine compartment is torn, fallen, or missing, you would get all kinds of engine smells pouring into your interior. If you are getting strong smells even with it in max a/c, that throws out that theory.

Have you check the coolant level lately? Maybe a leaky heater core. But that would be more "sweet" smelling than gas.

Sorry I can't help much,

Robb

 

[aldive]

The air is being pulled in from the cowl and if you have a fuel line problem under the hood, the smell could easily enter this way.

Check all the fuel lines good.

Good luck.....

 

[ozmedia]

The air is being pulled in from the cowl and if you have a fuel line problem under the hood, the smell could easily enter this way.

Check all the fuel lines good.

Good luck.....

The bladder in the fuel pressure regulator can also split and crack, this admits fuel vapour into the intake manifold and thus the A/C. Common with older Explorers, not sure about your mazda but it sounds like the same issue. As it worsens, the idle will have issues and you'll burn more gas too.

It's worth a vacuum test to see if there's leak down at the regulator, or pull the hoses and see if they have any fuel in them.